package com.xunwulian.base.util;

import org.apache.commons.lang3.StringUtils;

import java.security.MessageDigest;

public class MD5Util {

    private static final String hexDigits[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
            "e", "f"};


    /**
     * 字节数组转十六进制字串
     *
     * @param b 字节数组
     * @return 十六进制字串
     */
    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();

        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }

        return resultSb.toString();
    }

    /**
     * 字节转十六进制字串
     *
     * @param b 字节
     * @return 十六进制字串
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0) {
            n += 256;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    /**
     * MD5编码
     *
     * @param origin  要编码的字串
     * @param charset 编码类型
     * @return 编码后的字串
     */
    public static String MD5Encode(String origin, String charset) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (StringUtils.isBlank(charset)) {
                resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
            } else {
                resultString = byteArrayToHexString(md.digest(resultString.getBytes(charset)));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return resultString;
    }
}
